Carlina Velicer

Co-author: Mark Lesser

Mind the Gap: The Role of Beaver-Felled Canopy Openings in Facilitating Terrestrial Plant Invasions

Abstract - Castor canadensis (North American Beaver) is a keystone ecosystem engineer whose dam-building and foraging activities create or sustain riparian habitats. Beavers influence the competitive dynamics of the forest understory through tree felling, which creates canopy gaps, increasing light availability and reducing competition for soil and nutrients. Invasions of many common non-native plants increase in frequency and severity in the wake of canopy disturbance. Although invasive vegetation is common in riparian ecosystems across the US, it is unknown to what extent canopy gaps created by Beavers promote terrestrial plant invasions. Our objectives were to assess (1) the extent to which Beaver felling influenced light availability, (2) whether canopy gaps created by Beaver felling facilitated the spread of non-native herbaceous plants and woody shrubs, and (3) which invasive species took advantage of these gaps. Since Beaver-felled gaps increase light availability—potentially creating conditions conducive to the spread of non-native species—we hypothesized that Beaver herbivory promotes the spread of invasive herbaceous plants and shrubs. At a well-established beaver pond at the Huyck Preserve and Biological Research Station in east-central New York, we surveyed 5-m radial plots around 38 Beaver-felled and unfelled control trees. We measured tree diameter, canopy openness, soil pH, and the percent abundance of invasive plant species. Plots with Beaver-felled trees exhibited gaps in the forest canopy, resulting in significantly higher light levels than unfelled control plots. The total percent abundance of invasive herbaceous plants and shrubs was significantly higher in Beaver-felled plots than in controls, but only 3 of the 10 invasive species surveyed were drivers of this difference: Celastrus orbiculatus (Asiatic Bittersweet), Lonicera spp. (honeysuckles), and Berberis thunbergii (Japanese Barberry). Our findings reinforce the importance of light availability resulting from canopy disturbance, and facilitated by Beaver activity, in enabling terrestrial plant invasions.

Danielle Moloney

Co-author: Sean Grace

A Within-site Comparison of Intertidal and Subtidal Populations of Astrangia poculata

Abstract - Ocean temperatures are expected to rise 1–3 °C by the year 2100, and this shift warrants an immediate and greater understanding of marine-life resilience. High temperatures have been implicated in global declines of multiple marine populations, including corals, with 14% of global hard coral cover being lost in >10 years between 2009 and 2018 alone. Historically, most marine research on corals has focused on tropical species that tend to exist within narrow conditions for survival, in which there is little variation in the abiotic environment, including temperature, water chemistry, and light and nutrient levels. However, not all corals live under these precise conditions. This research project focuses on the temperate scleractinian coral Astrangia poculata (Northern Star Coral), abundantly found along the US east coast from Cape Cod to Florida. Northern Star Coral provides an interesting candidate for research due to its facultative symbiosis (ability to live with very low levels of symbionts in its tissue), its ability to live in both the intertidal and subtidal zones, and its winter quiescence (dormancy) period. We comparatively analyzed intertidal and subtidal populations of Northern Star Coral at a field site in Rhode Island. We subjected aposymbiotic intertidal and subtidal colonies to 5 temperature treatments (5 °C, 14 °C, 18 °C [control], 22 °C, and 27 °C), 4 of which might be considered thermally challenging based on historic averages in the region (reflected in the control treatment). We measured metabolic parameters including feeding response, dissolved oxygen use, and photosynthetic efficiency. Based on periodic exposure of intertidal individuals to extreme environmental variation when exposed to open air, we hypothesized that intertidal Northern Star Coral would have higher thermal tolerance at all experimental temperatures than subtidal Northern Star Coral. Preliminary results indicate that there is little difference between intertidal and subtidal physiological performances in laboratory tests. However, both intertidal and subtidal corals in the 5 °C treatment entered quiescence, allowing for measurements on dormant Northern Star Coral in the lab for the first time.

Indi-Anna Richardson

Co-authors: Maura Vanderputten, Senna Levy, Allyson Jackson, and Hanna Makowski

Autumnal Photosynthesis Duration Varies Amongst Native and Invasive Maples in Urban and Forest Environments

Abstract - This study investigated the phenological patterns of Acer rubrum (Red Maple), Acer saccharum (Sugar Maple), and Acer platanoides (Norway Maple) in urban and forest environments. Based on observation of leaf coloration and senescence, we analyzed the impact of microenvironments, species, and diameter at breast height on the timing and duration of the phenological processes. We collected data daily from 10 October 2024 through 20 November 2024 using bins to signify different phenological stages. We found that native Red Maple trees in an urban environment displayed the fastest rate of leaf senescence, likely due to the urban heat island effect. Native Sugar Maple trees in a forest environment maintained foliage longer than their urban counterparts. Invasive Norway Maple trees exhibited the largest variability in phenological timing, but they showed delayed senescence compared to their native counterparts. We also observed a positive correlation between diameter at breast height and delayed senescence across all species, suggesting that larger trees may have prolonged photosynthetic periods. These findings emphasize the impact of microclimates and tree size on phenological patterns and the competitive advantage of invasive species. Understanding these dynamics is crucial for the management of native and invasive species in a world of rapid global change with shifting environmental conditions.

Victoria Prouty

Co-authors: Jacob Warner, Donna Vogler, Faith Williams, Elayne Sepulveda, Alexandra Vlk, and Elizabeth Bastiaans

Changes in Shell Symmetry and Diet in Populations of the Wood Turtle, Glyptemys insculpta

Abstract -Factors contributing to population declines in herpetofauna across the northeastern US, such as anthropogenic disturbance, habitat degradation, and landscape fragmentation, may also be linked to changes in an organism’s physiology. We conducted field surveys at a highly disturbed site in Oneonta, NY, to locate, photograph, and collect carapace and claw samples from Glyptemys insculpta (Wood Turtle). We compared fluctuating asymmetry in the carapaces and plastrons of modern Wood Turtles to historical Wood Turtle specimens captured from a range of sites near the Oneonta region during the 1950s–1960s. Additionally, we conducted a stable isotope analysis of δ15N and δ13C in modern and historical Wood Turtle carapace and claw tissues. Our results revealed that modern turtles had the highest levels of asymmetry in both their carapaces and plastrons, and that the presence of a shell deformity substantially increased asymmetry. These results suggest that modern Wood Turtles may be exposed to suboptimal conditions during development, which may be increasing levels of asymmetry in both the carapace and plastron. This increase in asymmetry may be attributed to higher temperatures during incubation, population isolation and reduced gene flow, and stress from anthropogenic interference in their preferred habitats. Preliminary analyses of results from the stable isotope analysis of δ15N and δ13C suggest that the diets of contemporary Wood Turtles are different than those of historical Wood Turtles from the same geographic region, with historical Wood Turtles occupying higher trophic positions and consuming a greater proportion of high-nitrogen food sources. A shift in the diets of modern Wood Turtles may indicate that they do not have access to their preferred food sources and that they are not receiving the nutrients they need for successful survival and reproduction.

Ian Mowatt

Co-author: Joseph Staples

The Role of Climate in the Geographic Expansion of Ixodes scapularis: A Predictive Modeling Approach

Abstract - The geographic expansion of Ixodes scapularis (Blacklegged Tick), the primary vector of the bacteria Borrelia burgdorferi that is a major causative agent of Lyme disease, has been strongly influenced by climate change, reforestation, and shifts in host populations. This study integrates correlative and mechanistic modeling approaches to evaluate the species' future distribution under projected climate scenarios. MaxEnt modeling, utilizing WorldClim CMIP6 data (2041–2060), predicts continued northward expansion into southern Canada, driven by increasing minimum winter temperatures. Meanwhile, DYMEX simulations, incorporating physiological stress thresholds, confirm that for up to a +3 °C temperature increase, habitat suitability increases in northern latitudes while extreme summer heat may impose physiological limits on populations in the southeastern US. The results highlight potential declines in cold stress as a historical barrier to tick survival, supporting the likelihood of continued establishment in previously unsuitable areas such as northern New England, the Great Lakes region, and southern Canada. Alternatively, increasing summer heat stress may stabilize or slightly reduce tick populations in regions where temperatures exceed their thermal tolerance. These findings have significant public health implications, as the expanding range of Blacklegged Ticks may lead to increased Lyme disease risk in newly colonized areas. This study combines predictive modeling approaches to enhance assessments of future Blacklegged Tick distributions, emphasizing the need for proactive vector surveillance and targeted disease-prevention strategies in a changing climate.

Samantha Cronk

Co-authors: Mike Rubbo and Matthew Aiello-Lammens

Wildlife Use of Beaver Dams as Aquatic Crossings

Abstract - Castor canadensis (North American Beaver) play a vital role in shaping the environment. Their alterations to the areas they inhabit create new niches increasing biodiversity. However, the wetlands they create can also fragment terrestrial habitat and alter the migratory corridors of local wildlife. Conversely, the dams Beaver build may serve as crossings facilitating wildlife movement over aquatic barriers, potentially minimizing this fragmenting effect. To determine if wildlife use beaver dams to cross aquatic systems, we conducted a study using camera traps. We selected 13 beaver-dam sites across 6 properties in the Hudson Valley region of New York, ensuring that the dams completely spanned a water system and connected to upland areas on both sides. These sites were compared to areas with fallen logs that spanned streams (i.e., control sites). Cameras were deployed for a minimum of 15 weeks from June to November 2024. We categorized the camera events into bird and non-bird species and organized the species by taxonomic family. Preliminary analysis indicates that specific species, primarily Odocoileus virginianus (White-tailed Deer) and Procyon lotor (Raccoon), preferentially used beaver dams to cross streams. We are currently conducting an analysis to refine patterns of species use of dams as well as to identify the specific physical attributes of dams that enhance their use by wildlife.

Emmy Bedard

Co-author: Emily Nowicki

Examining the Change in Antibiotic Resistance of Pseudomonas putida in Soil Extract vs. Mueller–Hinton Media

Abstract - Antibiotic resistance is a complex global issue that results in infections becoming increasingly difficult to treat. This issue does not just impact people in healthcare settings but also occurs in animals and in the environment, including locations with little to no human activity. Clinical antibiotic resistance is tested using a standardized growth medium called Mueller–Hinton. This non-selective, consistently formulated medium has few inhibitors that interfere with the growth of microorganisms, making it an ideal choice for antibiotic susceptibility testing. Although using a standardized medium allows for easy comparison between labs regardless of location, antibiotic susceptibility is not currently tested using a medium that more closely resembles the environment where the resistant organism is usually found. This problem is true for both infectious bacteria as well as antibiotic-resistant bacteria isolated from the environment. The goal of this project was to prepare a soil-extract broth to represent the nutritional composition of soil and to use this medium to compare bacterial susceptibility to antibiotics to that in Mueller–Hinton medium. We conducted this research using Pseudomonas putida, a Gram-negative, rod-shaped, metabolically versatile bacterium that is found in many different soil and water sources and is intrinsically resistant to certain antibiotics. We found that P. putida had a higher tolerance to tetracycline and colistin, 2 commonly used antibiotics, when grown in the soil-extract broth. One possible explanation for this result could be the presence of humic acids in the soil extract, which have been shown to chemically change the antibiotic-resistance gene expression in bacteria living in soil. When humic acids were titrated into the Muller–Hinton medium, P. putida colistin tolerance increased to levels similar to those seen in soil-extract broth and was higher than the colistin tolerance observed when tested in Mueller–Hinton without the addition of humic acid. We are currently testing the hypothesis that gene expression changes in putative antibiotic-resistance genes are contributing to the observed differences between each growth medium.

Samuel Does

Co-authors: Thomas LaDuke, Emily Rollinson, and Howard Whidden

Camera vs. Live Traps: Comparing Methods for Small-Mammal Detection

Abstract - Studies of small mammals rely on live trapping to collect data, but risk trap bias brought on by the types of traps used. Camera traps are increasingly being used for the detection of small mammals due to their ease of use and potential to reduce trap bias. However, they have not been directly tested against traditional live-trapping methods thus far. To test their comparative efficacy, we deployed bucket-style camera traps concurrently with 4 styles of live traps over eight 3-day trapping periods spanning from July to October. During these periods, we also collected standard measurements from both camera images and in-hand specimens from live traps to test if the cameras could accurately collect standard measurements. The bucket camera was able to reliably capture clear images of small mammals that were consistently identifiable to a species level. The camera trap also captured a higher richness of mammals and showed a higher capture-success rate than any live-trap type tested. However, measurements collected from the camera trap do not appear to be reliable. The design’s ability to reduce trap bias is unclear; while it did show high richness, it is unknown if it accurately represented the true relative abundance of species on the site. Given their high capture success and relatively low cost, the bucket-style camera trap shows high potential for use in a variety of applications including site surveys and long-term monitoring.

Poster will be posted soon.